Characterization of chemical vapor deposited HfN multilayer coatings on cemented carbide cutting tools

The present study has been carried out in order to evaluate the tribological behavior of HfN-based multilayer-coated tools used for milling. The initial results of the wear behavior of multilayer HfN coatings, during the laboratory friction and wear tests conducted at room temperature against WC as tribological pair, are reported. As part of the characterization of the mechanical properties of the coatings, Vickers microindentation tests were also carried out employing loads in the range of 0.01–10 N, in order to evaluate the composite hardness of the coating-substrate systems. Information regarding the absolute hardness of the HfN and TiCN monolayer films has been obtained employing a model recently developed by one of the authors. This information is then used in order to determine the properties of the HfN/TiCN multilayer coating. It has been found that the wear volume of the single layer HfN coatings is approximately 15 times greater than the wear volume corresponding to the HfN/TiCN for the same amount of cycles.